The virus family Paramyxoviridae includes both human (measles, mumps, paraNDV and respiratory syncytial virus) and animal pathogens (Newcastle disease virus and rinderpest virus) that cause significant impact on public health as well as the global economy (Lamb et al., 2007, Paramyxoviridae: The viruses and Their Replication, p. 1449-1496). Members of this virus family are defined by having a monopartite, negative sense, single-stranded RNA genome. The Paramyxoviridae family consists of two subfamilies namely Paramyxovirinae and Pneumovirinae. Owing to recent reclassification, the subfamily Paramyxovirinae includes five genera, i.e. Morbillivirus, Henipavirus, Rubulavirus, Respirovirus and Avulavirus while Pneumovirinae includes Pneumovirus and Metapneumovirus (Mayo, 2002, Arch Virol 147:1655-63). Avian paramyxoviruses (APMV) are classified in the genus Avulavirus and comprise nine antigenically distinct serotypes that have been defined using hemagglutination inhibition (HI) tests (Alexander, 1988, Newcastle disease, p. x, 378 p). Of the nine serotypes, isolates belonging to the APMV-1 subtype can cause a devastating disease in commercial poultry and are classified as velogenic Newcastle disease virus (NDV). Milder forms of NDV are designated as mesogenic and lentogenic isolates, wherein the latter form is mostly asymptomatic in domestic poultry. The genomic RNA of NDV contains genes encoding six proteins: HN (hemagglutinin-neuraminidase), NP (nucleocapsid protein), P (phosphoprotein), M (matrix protein), F (fusion protein), and L (RNA-dependent RNA polymerse).
Viral vector vaccines represent one of the most rapidly growing areas in vaccine development. Many vaccines in clinical development for major global infectious diseases, HIV, tuberculosis and malaria, are viral vectors. The disadvantage of currently used viral vectors is the existence of maternally derived antibodies or antibodies acquired due to a past infection.
Recently, plants and algae have been investigated as a source for the production of therapeutic agents such as vaccines, antibodies, and biopharmaceuticals. These plant and algae expression systems provide several advantages. For example, deriving vaccines from plant or algae expression products can eliminate the risk of contamination with animal pathogens, provide a heat-stable environment, and would avoid injection-related hazards if administered as an edible agent (Thanavala et al., Expert Rev. Vaccines 2006, 5, 249-260). In addition, plants or algae can be grown on a large scale and can utilize existing cultivation, harvest, and storage facilities. Furthermore, there is a lower cost of production and processing to derive therapeutic agents from plants (Giddings et al., Nature Biotech. 2000, 18, 1151-1155) or algae. The F and HN proteins of NDV were expressed in potato plants for developing edible vaccine against NDV (Berinstein A., et al., 2005, Vaccine 23: 5583-6689). WO2004/098533 discloses the expression of the NDV HN antigen and the Avian Influenza Virus HA antigen in tobacco plants. US patent application publication No. US2010/0189731 discloses the expression of Avian Influenza Virus HA antigen in duckweed plants.
Development of vaccines, antibodies, proteins, and biopharmaceuticals from plants or algae is far from a remedial process, and there are numerous obstacles that are commonly associated with such vaccine production. Limitations to successfully producing plant vaccines include low yield of the bioproduct or expressed antigen (Chargelegue et al., Trends in Plant Science 2001, 6, 495-496), protein instability, inconsistencies in product quality (Schillberg et al., Vaccine 2005, 23, 1764-1769), and insufficient capacity to produce viral-like products of expected size and immunogenicity (Arntzen et al., Vaccine 2005, 23, 1753-1756). In order to address these problems, codon optimization, careful approaches to harvesting and purifying plant or algae products, use of plant parts such as chloroplasts to increase uptake of the material, and improved subcellular targeting are all being considered as potential strategies (Koprowski, Vaccine 2005, 23, 1757-1763).
Considering the potential effect of animal pathogens, such as NDV on public health and the economy, methods of preventing infection and protecting animals are needed. Moreover, there is a need for an effective vaccine against the pathogens and a suitable method for making the vaccine.